In general, a hermetic compressor is a compressor provided with a motor unit disposed in a hermetic container for generating a driving force, and a compression unit operated by receiving the driving force from the motor unit. The is hermetic compressors may be categorized into a reciprocating type, a rotary type, a vane type and a scroll type according to the compression mechanism with respect to a refrigerant as a compressible fluid.
The reciprocating compressor is configured such that a connecting rod is coupled to a crankshaft of the motor unit and a piston is coupled to the connecting rod, so that a rotational force of the motor unit is converted into a linear motion of the piston. The connecting rod has one end rotatably coupled to the piston and another end rotatably inserted into a pin of the crankshaft.
However, the another end of the connecting rod should be inserted into the pin of the crankshaft for assembly. Accordingly, in order to couple the pin of the crankshaft to the connecting rod, an annular connecting portion having a diameter larger than that of the pin of the crankshaft should be formed at the end of the connecting rod. Further, between an inner circumferential surface of the annular connecting portion and an outer circumferential surface of the pin, a sleeve as thick as an interval therebetween is inserted so that the rotational force of the crankshaft is transferred to the connecting rod.